Body Sync Inc. is a chain of gyms. It offers a fitness package that allows its members to use the gym facilities for 12 months by paying only for 10 months. Included in the package are two health checkups and a gym kit. These add-ons by themselves are not very valuable, but as a package they can enhance the perceived value of the service offerings. In this case, Body Sync's primary value driver is:.
A. learning-curve effects.
B. availability of complements.
C. experience-curve effects.
D. economies of scale.